宽温域下氟醚橡胶的加速老化行为和机理研究

Investigation on accelerated aging behavior and mechanism of fluoroether rubber under wide temperature range

基于氟醚橡胶使用环境的特殊性,从物理和化学角度,在宽温域(-40~225℃)条件下对某国产氟醚橡胶在4050航空润滑油中老化后的质量、力学性能、化学结构、元素组成及热稳定性等有关参数进行了研究,分析了老化温度和老化时间对氟醚橡胶性能的影响规律。结果表明:在相对较宽温域-25~200℃内氟醚橡胶的耐介质老化性能优异,其物化性能在长期老化过程中保持稳定;当老化温度达200℃以上时,溶胀和氧化反应增强,随着老化时间的增加,材料逐渐由软而韧变为硬而脆;特别是在高温225℃下,脱氟化氢反应导致大量C-F键断裂,F元素含量显著减少,同时氧化反应增强并生成C=O键,导致O元素含量增多;低温老化过程中氟醚橡胶的质量、化学结构及元素含量基本不变,但-40℃时的玻璃化转变行为会导致力学性能的下降。

Based on the particularity of the use environment of fluoroether rubber, from a physical and chemicalpoint of view, the quality, mechanical properties, and chemical related parameters such as structure, elementcomposition and thermal stability were studied, and the influence of aging temperature and aging time on theproperties of fluoroether rubber was analyzed. The influence of temperature and aging time on the properties offluoroether rubber is analyzed. The results show that: fluoroether rubber has excellent resistance to lubricating oilaging, and its physical and chemical properties remain stable during long-term aging in the temperature range of-25-200℃;When aging temperature reaches 200℃ and above, the swelling and oxidation reaction accelerate, thematerial will gradually change from soft and tough to hard and brittle with the aging time. Especially at theextremely high temperature of 225℃, dehydrofluorination reaction causes the fracture of C-F bonds, the content ofF element significantly decreases. Meanwhile, the oxidation reaction is enhanced, forming the C=O bonds, so thatthe content of O element increases;The quality, chemical structure and element content of fluoroether rubberbasically remain unchanged at low aging temperatures, and glass transition occurred at-40℃, resulting in thereduction of mechanical properties.